/*
 * Copyright (c) 2009, Hamish Morgan. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * 3. Neither the name of the University of Sussex nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */
package locusts.server.physics;

import java.io.Serializable;
import locusts.common.entities.Entity;

/**
 * A <tt>Joint</tt> object specifies that two entities are connected some way
 * in the psudo-physics system (<tt>PhysicsSystem</tt>). Once created at added
 * two the <tt>PhysicsSystem</tt> the object implementing <tt>Joint</tt>
 * should attempt to inforce some positional relationship between the two
 * entities, such as orientation and position.
 *
 * @author Hamish Morgan
 * @see PhysicsSystem
 *
 */
public interface Joint extends Cloneable, Serializable {
 
    /**
     * Will be called by the game engine once per game update cycle. This
     * method should, if required, update the position and orientation of the
     * entities to preserve their relationship.
     *
     * @param period
     */
    void update(double period);

    /**
     * Accessor to the first Entity.
     *
     * @return the first Entity.
     */
    Entity getEntityA();

    /**
     * Accessor to the second Entity.
     *
     * @return the second Entity.
     */
    Entity getEntityB();
}
